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Megasquirt vs Microsquirt (for a 6 cyl)


=jon=

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Hi,

In my oddball 90 I have a ford essex v6, currently running an electronic dizzy and a weber twin choke carb - it goes reasonably well, makes a rather nice noise but is only slightly more economical than an RV8... One of of the ways of hopefully getting a bit more grunt and a bit more mpg (although I'm not hoping for miracles ;) ) is to go for megasquirt...

I should be able to get a trigger wheel and sensor for the crank, ford v6 EDIS which will take care of the ignition side, and potentially a yank throttle body injection unit at some point in the future to replace the carb.

With that in mind, looking round microsquirt systems seem to be pretty cheap - £250 pre-built vs. £400odd for a full fat one. Will the microsquirt run everything I want to OK? I know it's cut down a bit but don't want to end up crippling myself...

I'm not hugely up on MS, but understand standalone ECU systems from my other toy, a turbo'd MX5 which is running an alternative full standalone ECU :)

Any advice appreciated!

Thanks

Jon

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Microsquirt is an MS2 in a small form with a few limitations - one is injector current, the other is the lack of an internal MAP sensor. I don't think it can be (easily) modified to control EDIS.

So, a few things for you to research:

- How much current would 6 injectors be needing on your engine? I know it's very borderline for a Rover V8.

- What's the deal with the MAP sensor?

- Can it run EDIS?

More local factors are the fact that MS2 and MicroSquirt are not common fare round these parts, whereas a "normal" MS bought from Nige running the same code as everyone else gives you a broader support base. A Nige-spec MS will run your V6 on EDIS6 out of the box.

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OK - this is the kind of info that I'm after :)

For the injectors - the only option is throttle body injection, so there's only 2 injectors, so not so much of an issue.. For a MAP sensor I think you use an external one - bosch or similar...

I've PM'd Nige already as he seems to have a load of v6 EDIS units on ebay at the moment :)

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Ah yes, the EDIS 6 are only 75% as good as a EDIS 8 IMVHO :P

:P

Alternative ebay vendors of edis6 packs are available you know ;)

Can you not fit an EFI setup from a later Granada?

I think the EFI cars were all Cologne v6's, not Essex, but I'll have a check...

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Here's a partially related question that has always interested me:

Why the internal MAP sensor?

Would it not be better to use a sensor fitted to the manifold itself? More accurate?

I was surprised when I found out it was located in the ecu itself and have always wondered if there was a specific reason!

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Packaging and conformity mainly - if it's a standard component and on board then they are all the same - so the firmware/software can be simpler.

With the ECU in my other car, the sensor is external, and you can use any type - but you have to go through a calibration process to define it when you set it up initially.

In theory the pipe run should be short, but someone on the MS forums did some testing and pretty much proved that the length of pipe between the manifold and sensor didn't really make any difference to the results...

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Also, if you have it right on the intake, you can get fluttering in the MAP value, which makes MS do funny things, quite a few people run a small fuel filter in the MAP line to give it some damping (I don't though!)

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EDIS-6 works great on the Essex. If you can find the original Ford pressed metal timing wheel from the Escort, it will bolt between the two front pulleys after about 10 seconds filing.

Sadly NLA from Ford IIRC. I never got the multispark option to work, but I don't know if the V6 module doesn't support it generally, or just the modules that I had.

I have seen more than one Essex with port injection, one was in an 88" built by a guy who spent his working hours welding stainless. I don't thinks there much benefit over TBI though, as the plenum volume is very small and the intake tracts are very short, I suspect you could even get worse mixture variation rather than better. The essex doesn't have the silly V8 firing order, so you don't get the same adjacent cylinder firing problems.

The Chevy TBI unit is easy to fit on the standard manifold, or on a 4-barrel one, with homemade adapters. Unless you're going to make a LOT of power, you'll want the smallest chevy injectors you can find (35lb?).

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Thanks for the feedback TSD - your thread (and build pages) have been my reference and inspiration for a while now :)

Which mark escort is the timing wheel from, can you remember?

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Looking back into the mists of time...

"The 1.8 CVH Sierra seems to have the only external 36-1 wheel you'll
get from a scrap yard. However if you want a pressed steel one order
part no. 6523986 (91XM 6K339AA) from Ford, it was fitted inside 16v
DOHC engines. It cost me 12.75 UKP inc VAT and is 2mm thick, 168 OD,
94 ID. Tooth height 17mm."

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Not really - I've been discussing it on and off with TSD via PM for about 6 months now, and still haven't got any of the other bits- a week or so won't really make a lot of difference!

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  • 2 months later...

OK - things are moving again now (and the forum is working again too!)

Mr. FridgeFreezer should be posting me a suitable timing wheel at some point this week :)

What else am I going to need, for just spark control at the moment:

Megasquirt unit itself.

Ford v6 EDIS unit

v6 coilpacks of some description, and suitable plug leads?

VR sensor for the trigger wheel, bracket and loom.

Then to go throttle body injection:

TBI unit (probably a twin injector GM unit from the US)

Air temp sensor (if it's not on the TBI)

Throttle position sensor (if not on the TBI)

Fuel injection pump

Patience and beer :)

Anything else? H f H is selling some of the v6 bits on ebay at the moment, so that should be reasonably straightforward...

Where's the usual mounting point for the MS in the cabin? Under the seat box, or is it of risk of getting wet in there?

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Good point. I could probably get away with one as the exhaust joins before the gearbox, and with only 2 injectors I doubt I could trim by bank anyway. Will MS do fuel trims OK on a narrowband, or is a wideband a lot better for the initial setup? I could probably pinch the wideband + controller from my other car if really needed...

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Narrow band is fine, if it was a pure race bred engine I would go wide, but it's not, is it :)

I only said a couple because assuming you were using one, it can be quite easy to kill if you get the mixture wrong at any point... :)

Don't buy the really cheap nasty ones, they just don't last at all.

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